Why not use garden hangers to enhance your yard? Hangers or "shepherd's hooks" allow you to place accessories almost anywhere without disturbing trees or a perfectly manicured landscape. They also help you create squirrel-free feeding stations (when used with a baffle) because you can place them in the open where squirrels cannot launch an aerial attack on the feeder.
(Strategic placement of feeders throughout your yard can help reduce competition and territorial behaviors while also allowing you to view your visiting birds from multiple windows. Remember to offer a variety of feeder types to attract the most variety.)
Make a place for charming items like a butterfly house.
Suspend pleasant-sounding wind chimes or kinetic spinners.